Characterization of damage and failure during the pull-out of a reinforcement bar by acoustic emission and numerical simulation

The presented initiative is an attempt to combine both, numerical simulation and experimental techniques, to further understand the phenomena which characterize the pull-out of a reinforcement bar from the surrounding concrete ‘matrix’. Based on the Finite-Element Method, non-linear constituitive relations are introduced to reflect the sliding of the reinforcement bar inside the concrete and to account for fracture in the concrete mass. The experimental setup is equipped with quantitative acoustic emission. The spatial and temporal location of the sliding and fracture events is recoded during the test and the underlying fracture mode for the acoustic events is evaluated via a relative moment tensor inversion technique. Thus, characteristic values, such as the relative amount of the occuring fracture modes, the specific energy release rates separated for the generic fracture modes, and the specific location of the degradation events are available from both approaches. The first results of this ongoing research effort are very encouraging and strongly support the combined experimental and numerical investigation of such complex challenges.